For certain testing purposes, it is necessary to produce optical radiation having intensity and spectral characteristics similar to those of a missile or jet aircraft engine. One such test involves determining the performance of infrared (IR) detectors which warn aircraft of attack by enemy aircraft and/or missiles. The only prior art technique to our knowledge involves firing the engine or missile. Although this technique produces the most realistic radiation characteristics, it is very costly and cumbersome. In addition, the prior art method of simulating missile plumes imposes unrealistic test configurations because of missile/launch safety requirements. It is not feasible to impose such safety requirements on personnel who are, for example, testing infrared detectors.
The requirement to actually fire a missile or start an engine necessitates the use of special test sites that do not permit realistic test configurations in many situations. In particular, the test site is usually located close to the ground and the position of the missile or aircraft engine must be fixed for each individual test. If it is desired to change the orientation of the missile or engine relative to the horizon, or to change the altitude of the missile or aircraft engine, considerable time and effort must be expended. In certain instances, it may even be necessary to actually fly the aircraft or launch the missile, merely for IR detector testing purposes.
A further defect with the prior art technique is that it does not usually enable tests to be performed in environments wherein there is a background, jet aircraft plume on which is superimposed a missile plume. Such a situation frequently exists in real practice and it is desirable to determine the response of a missile and jet aircraft plume detector to such a situation. A further disadvantage of the prior art technique, with regard to missiles, is that a fired missile cannot usually be reused, whereby the test costs are very high. For all of these reasons, the prior art technique has proven to be far less than optimum.
It is, accordingly, an object of the present invention to provide an apparatus for and method of simulating the intensity and spectral characteristics of a missile and/or jet aircraft plume.
A further object of the invention is to provide a new and improved apparatus for and method of testing IR detectors responsive to jet aircraft and/or missile plumes.
An additional object of the invention is to provide an apparatus for and method of simulating the plume of a jet aircraft and/or missile wherein the need to actually fire the aircraft engine or missile is obviated.
A further object of the invention is to provide an apparatus for and method of simulating a jet aircraft, background plume on which is superimposed a missile plume.
A further object of the invention is to provide an apparatus for simulating a plume of jet aircraft and/or missile as it is changing range relative to a target location.
Yet another object of the invention is to provide a relatively inexpensive apparatus for simulating the plume of a jet aircraft and/or missile wherein the orientation of the plume can be easily varied.
Yet another object of the invention is to provide an apparatus for and method of simulating the plume of a jet aircraft and/or missile without imposing safety constraints involved in operating aircraft and launching missiles.
An additional object of the invention is to provide an apparatus for and method of simulating the plume of a jet aircraft and/or missile wherein the device can be located and the method can be performed in a convenient location that allows realistic testing of a detector for the plumes.
A further object of the invention is to provide a re-usable apparatus for simulating the plume of a jet aircraft and/or missile.